Wallboard



Julygl, 1937.

J. FLETCHER 2,086,862

WALLBOARD Filed Aug. 22, 1955 JWM/Ha Patented July 13, 1937 2,086,862

, UNITED sTATEs PATENT OFFICE WALLBOARD John Fletcher, Kenmore, N. Y.,assigner to Plastcrgon Wall Board Company, Buialo, N. Y., a corporationof New York Application August 22, 1935, Serial No. 37,351

12 Claims. (Cl. 91-68) This invention relates to wallboard, and parmumexpansion and contraction when assemticularly to a composition wallboardhaving as a bled as part of a wall construction, and with v part thereofa sheet of open pore fiber insulating which the cracks between abuttingedges of adboard. Heretofore, attempts have been made to jacent sheetsmay be easily lled in a manner 5 apply a plastic gypsum mixture to aface of suchr to seal the cracks and provide a durable, conopen pore berinsulating board, but the product tinuous gypsum finish from one sheetto the other.

obtained has been unsatisfactory because it has Various other objectsand advantages will be been impossible to avoid cracking of the gypsumapparent from the following description of excoating during handling ofthe sheet, and beamples of the invention, and the novel features causeof the unequal expansion and contraction will be particularly pointedout hereinafter in 10 of the coating and open pore board. The gypsumconnection with the appended claims.

mixtures heretofore used for this purpose have In the accompanyingdrawing:

' been brittle, with a tendency to disintegrate and Fig. l is asectional elevation through a por- Separate from the porous and fibroussurface of tion of asheet of Wallboard constructed in accord- 5 the openpore board during transportation and ance with this invention; and 15handling, prior to and during the application of Fig. 2 is a sectionalelevation through a part the board to a wall construction. A gypsumsurof a Wall construction utilizing this improved face or face on `awallboard is often very deboard, and illustrating the manner of fillingthe sirable, but because of the expansion and concracks and forming acontinuous gypsum iinish traction of the flberboard, it is also dicultto between adjacent sheets of said board. keep the cracks betweenabutting edges of ad- In accordance with this invention Iimpregnatejacent sheets of such board filled with a gypsum a sheet of open poreber insulating board with mixture so as to form a continuous union beasuitable stiiening agent, and then apply to a tween the 4gypsum coatingson the adjacent or' face of such board a plastic coating containingabutting sheets. When the sheets contract, the calcined gypsum and anadhesive. S0 that the 25 lling tends to separate from the edge of oneadhesive of the coating will adhere firmly to the sheet or the other andform an objectionable stiffened board. By impregnating the board crackin the gypsum surface or coating. with a stiffening agent, its expansionand con- An object of the invention is to provide an imtraction isgreatly restricted, which reduces the 0 proved wallboard which will havea gypsum ntendency of the gypsum coating to crack or sep- 30 ishedsurface, With which the development of arate from the board. Preferably,I impregnate cracks and disintegration during handling oi' a sheet ofopen pore fiber insulating board with the board will be substantiallyprevented, with a readily soluble Sienllg resin, and this mwhichseparation of the gypsum coating or finish pregnation, in Someinstances, is preferably dis- ;5 from the board will be substantiallyprevented, tributed throughout substantially the entire 35 which willhave maximum strength, rigidity and board, although 43some of thedesirable results durability, which will have substantial resistance maybe obtained to Some extent through imto destructive insects, and whichwi11 be relapresu-ation only 0f a Surface layer of the board. tivelysimple, and inexpensive. I prefer to carry out the impregnation by apl0Another object of the invention is to provi-de plying t0 the' board aSolution of the resin in a 40 5 mixture to provide a continuous gypsumsurface an improved wallboard having a gypsum coating volatile solvent,because I have found that by or huish, with vwhich the cracks betweenabutusing the resin Solution. great Strength and rigidting edges ofadjacent sheets as applied to a, ity of the board is obtained. To a faceof this wall construction, may be lled with a gypsum board, Which Shouldbe an impregnated facial apply the coating of a plastic mass containing45 from one sheet to the other, with which the de- Calcined gypsum withan adhesive, and the most velopment of cracks in the gypsum coating 0rsatisfactory adhesives are resinous solutions confinish at the abuttingedges of the sheets will be taining a solvent for the resin with Whichthe substantially reduced or prevented, and with berboard isimpregnated. The inclusion in the 30 which greater adhesion between thecrack filler gypsum mixture f a quantity 0f fbI'OllS, DOII- 50 and theboards may be obtained. metallic minerals such as fibrous types of am-Another object of the invention is to provide an phibole, serpentine andchrysotile, is advantaimproved method of making wallboard, which geousand adds materially to the strength and will produce a superiorWallboard having a gyptenacity of the coating. When `a plastic mass sumcoating or finish, maximum strength, minior mixture of calcined gypsum,with or without added fibers, and such a resinous solution is applied tothe impregnated board, the solvent in the resinous solution of theplastic mass, where it contacts with the impregnated board, will softenor partially dissolve the resinous impregnating agent of the board atapproximately the surface of the board, and then when the solvent isevaporated or absorbed a very rm union between the coating and the boardis obtained.

The resinous adhesive used in the gypsum mixture greatly increases thestrength, durability, and rigidity of the gypsum coating, because itcauses greater cohesion between the particles in the mixture of thecoating. 'I'he board, because of its impregnation with the resin, willbe largely unaffected byatmospheric and temperature changes and,therefore, the tendency of the gypsum coating to crack or chip offduring use will be reduced or prevented. The tendency of the coating tocrack and chip is also reduced by the fibrous non-metallic mineralswhich may advantageously be included with the gypsum in the lcoatingmixture.

Among the resins which are suitable'for impregnation of the berboard, aswell as for mixture with the calcined gypsum forming the coating, may beparticularly mentioned the natural resins such as shellac, rosin, gumaccroids, manila gum and kauri gum, and among the synthetic resins maybe particularly mentioned the phenol-aldehyde resins, the polybasicacid-polyhydric alcohol, fatty acid type of resins, and theurea-aldehyde type of resins. The solvent used for the resin with whichthe board is impregnated should preferably be a readily volatilesolvent. Alcohol is a very satisfactory and inexpensive, yet volatile,solvent for this purpose.

As one example of the invention, a sheet of open pore fiber insulatingboard is thoroughly impregnated with a solution of one of the abovementioned resins vin alcohol. Then to a face of such an impregnatedsheet I apply a coating, in plastic form, which may be prepared asfollows:

Approximately parts by weight of dry calcined gypsum is mixed with 50parts of a resin solution containing 20 parts of shellac-and 30 parts ofalcohol. 'Ihis plastic gypsum mass may be applied to a face of theimpregnated board by trowel or brush and levelled out on the board. Thethickness of the coating may be whatever is desired, but I have foundthat it may vary for practical purposes between 1,@4 of an inch to ys ofan inch Without-danger of the surface coating cracking. Preferably, theimpregnated board is dried somewhat after impregnation, although with areadily Volatile solvent, suflicient air drying may occur after theimpregnation before coating can be applied thereto.

The alcohol or other solvent in the gypsum plastic coat will, whereveritcontacts with the fiber board, soften or partially dissolve thealcohol soluble resin with which the board was impregnated, and then asthe plastic mass or coating hardens and the alcohol or solventevaporates, there will be a firm and unitary union between the resin ofthe gypsum coating and the resin With which the board is impregnated. Inaddtion, the resin in the gypsum coating will increase the cohesionbetween the gypsum particles, and thus provide a very hard gypsum finishor coating on the board which adheres to the board with a maximum offirmness. Any of the other resins may be employed in a similar manner,both for the impregnation of the board and for the preparation andapplication of the gypsum coating.

' When the improved gypsum wallboard is applied to a wall construction,the sheets are usually secured to a wall or basicl structure by nailsdriven through the board into the basic structure. In Fig. 2 I haveillustrated a simple manner by which this improved board may be attachedto a basic structure without the objectionable feature of having theattaching nails visible on the exterior of the wall. Referring now toFig. 2, the portion of a Wall construction in which two sheets I0 ofopen pore, fiber insulating board that have been impregnated and coatedwith a gypsum iinish or coating in accordance with this invention, arebrought together against a basic structure I2 so as to approximatelyabut edge to edge and lie flat against the basic structure I2 along theabutting edges of the improved board.

A plurality of nails I3 may then be driven through the sheets III intothe basic structure I2 at the abutting edges of the sheets, the nailsbeing preferably started adjacent the base of the coatings and drivensomewhat diagonally through the impregnated open pore berboard sheets I0into the basic structure I2, as shown clearly in Fig. 2. nails will notpass through the gypsum finish or coatings on the impro-ved board, butlargely through the impregnated basic sheets IIJ. Since the impregnatedsheets now have greater strength and rigidity, it is possible to passthe nails through the end edges of the impregnated sheets and stillobtain a. satisfactory attachment between the board and the basicstructure I2.

The crack or space between the adjacent edges of the improved wallboardmay then be lled with a plastic mass I4, which preferably should containcalcined gypsum mixed with an adhesive such as a resinous solutioncontaining a solvent for the resin with which the sheets I I! areimpregnated, and therefore the mass I4 may advantageously be of the sameplastic composition as that of the gypsum coating I I on the impregnatedboard. The solvent in the plastic mass will soften, and form a firmunion with, the resin with which the open pore sheets I0 are impregnatedand also the resin of the coatings I I. If it becomes necessary to driveattaching nails I5 through a face of the coated sheets, the nails arepreferably countersunk at their heads and the countersunk holes I6 thenfilled with a plastic mass similar to the crack ller I4.

It will be understood that various changes in the details and materials,which have been herein described and illustrated in order to explain thenature of the invention, may be made by those skilled in the art Withinthe principle and scope of the invention as expressed in the appendedclaims.

' I claim as my invention:

1. An improved wallboard comprising a sheet of open pore, ber insulatingboard impregnated with a stiiening resin solution, and having anadherent surface coating of a mixture containing calcined gypsum and aresin solution in which the impregnating resin is soluble.

2. An improved wallboard comprising a sheet of open pore, ber insulatingboard impregnated with an alcohol soluble stiffening agent, and having ahardened surface coating which has been` applied thereto while plasticand containing calcined gypsum mixed with an alcohol-containing, resinsolution, whereby the alcohol in the applied plastic coating will unitethe coating firmly to the open pore 'board through the impregnatingagent therein.

With this arrangement the 3. The method of making an improved wallboardwhich comprises impregnating a sheet of open pore, fiber insulatingboard with a solution 'ing resin is soluble, whereby when the plasticcoating hardens the resin intermixed therewith increases the cohesionbetween the gypsum particles and the solution in the plastic coatingwill soften and formv a firm union with the resin impregnating theberboard. A

4. The method of making an improved wallboard which comprisesimpregnating a sheet of open pore, fiber insulatingboard with a solutionof a stiffening resin in a volatile solvent, substantially drying theimpregnated board to harden the resin therein, and then applying to aface of the impregnatedsheet a plastic coating containing a mixture ofcalcined gypsum with a resinous solution in which the'impregnating agentis soluble, and then hardening the coating, whereby the resin intermixedwith the gypsum will increasey the cohesion between the gypsum particlesand the solution intermixed with the resin will soften and form a unionbetween the resin-con,- taining coating and the impregnatingresin ofthesheet.

5. The method of preparing an improved wallboard which comprisesimpregnating a sheet of open pore, ber insulating board with an alcoholsolution of a stiiening resin, and .then applying to a face of theimpregnated sheet a coating of a plastic mass containing a mixture ofcalcined gypsum with a resinous solution containing alcohol, and thenhardening said coating.

6. The method of preparing an improved wall- V board which comprisesimpregnating a sheet of I' soluble stiiening resin, and then applying toa lface'of the impregnated sheet, a coating of a plastic' masscontainingv calcined gypsum mixed with a solution of shellac in alcoholland then hardening said coating.

8. The method of making an improved wallboard which comprisesimpregnating a sheet of open pore, fiber wallboard with an alcoholsoluble resin to stiffen said sheet, and then applying to a face of theimpregnated sheet. a. coating of a plastic mass containing calcinedgypsum, shellac and alcohol approximately in the proportions of 100parts by weight of dry calcined gypsum and 50 parts of a resin solutioncontaining 20l parts of shellac and 30 parts of alcohol, and thenhardenlng the coating.

9. An improved wallboard comprising a sheet of open pore, ber insulatingboard impregnated with a stiffening resin which is soluble in a volatilesolvent, and having on a face thereof, a coating containing a mixture ofcalcined gypsum with a resin solution containing a solvent for theimpregnating resin, whereby said solvent in`the coating mixture willsoftenv and form a union with the impregnating resin in-said sheet.

10. An improved wallboard comprising a sheet of open pore, berinsulating board impregnated with an alcohol solution containing astiifening resin, and having on a face thereof a coating of Y a mixture,applied while plastic, containing calcined gypsum intermixed with analcohol solution of a resin, whereby the alcohol of the plastic coatingwill soften the impregnating resin of said sheet and form a firm unionbetween the coating and the sheet.

11. An improved wallboard comprising a sheet of open pore, fiberinsulating board having at least a surface layer thereof impregnatedwith a soluble resin, and having on said impregnated surface layer, anadherent coating, applied while plastic, containing a mixture ofcalcined gypsum with a resinous solution including a solvent forthevimpregnating resin of saidsheet, whereby the solvent in said plasticcoating will soften the impregnating resin on said surface layer of saidsheet and form a irm union between it and the 4 resin in said coating.

12. An improved wallboard comprising a sheet of open pore, berinsulating board impregnated with a stiiening agent, and' having on asurface thereof a coating, applied while plastic, containing a mixtureof calcined gypsum and a solvent for said agent.

^ JOHN FLETCHER..

